This is an update on my Q accident and subsequent attempts to re-queen:
The "accident hive" turned out to be queen-less and developed laying workers - so I emptied the hive 50 yards from the apiary.
Inspection of apideas and a nuc, started with salvaged sealed emergency Q cells, showed that the Qs had hatched but that there were no signs of her or eggs about two weeks after hatching , despite the best warm, sunny, windless May for a long time. A couple of emergency Q cells that hatched in an incubator were, indeed decent looking Qs. Would laying workers have found their way back to the apiary and killed newly hatched apidea Qs (I used nurse bees from other hives in the apideas but the nuc had brood and bees from the "accident hive")? I can understand laying workers killing the emergency Q hatching in the nuc with its associated frame bees.